1. Field of the Invention
The present invention relates to a sewage pump, and more particularly to a sewage pump that additionally comprises an auxiliary blade set so that the sewage pump performs a two-step smashing function to improve durability of the sewage pump, the breaking efficiency and the sewage draining efficiency.
2. Description of Related Art
Conventional sewage pumps as shown in FIGS. 1 and 2 each substantially has a central shaft 1 of a motor sleeved with a water paddle disk 2 and a wheel blade 3 that are driven to rotate by the driving of motor. The water paddle disk 2 has multiple paddle sheets arranged in whirl on its lower surface and is accommodated inside a paddle chamber 5 of a lower base 4. The wheel blade 3 has multiple blade sheets in a certain number and is mounted in a precipitation inlet 6 below the paddle chamber 5. Moreover, a gear ring 7 is attached on an inner wall of the precipitation inlet 6. A precipitation outlet 8 is defined at one side of the paddle chamber 5 to connect to a universal joint with drain pipe (now shown). By having the above-described structure, the central shaft 1 drives the water paddle disk 2 and the wheel blade 3 to rotate and to cause current suction function to drain the precipitation via the precipitation inlet 6 below the paddle chamber 5 when the motor of sewage pump operates. Meanwhile, the wheel blade 3 cooperates with the gear ring 7 to smash and scatter the precipitation and then the paddle sheets on the water paddle disk 2 push the precipitation to the precipitation outlet 8 to drain out via the drain pipe. Therefore, the precipitation on a bottom of the sewage tank can be eliminated.
However, the conventional sewage pump can not perform sufficient smashing efficiency and some large precipitation pieces stick to the water paddle disk 2 because only one stage of smashing by the wheel blade cooperating with the gear ring is short in processing period and insufficient to completely smash the precipitation. Therefore, the large pieces of the precipitation get stuck to the paddle sheets of the water paddle disk 2. Thus, the precipitation can not be drained out smoothly and the operation of the water paddle disk 2 is interrupted. In these cases, the smashing efficiency is reduced and malfunction rate is increased.
Additionally, still another conventional sewage pump as disclosed in U.S. Pat. No. 7,159,806 has a wheel blade mounted in the precipitation inlet on the lower base of the pump to smash and scatter the precipitation sucked into the sewage pump. Although the wheel blade operates upward and downward in reciprocation when smashing, the efficiency is still poor and the precipitation can not be smashed and eliminated completely.